Metacommunities structure of stream ichthyofauna of the Upper Paranapanema river basin

Abstract

River networks can be considered ecological corridors featuring hierarchical dendritic landscapes for organisms. Based on this we assume that riverine fish movement in these systems would be greater in the main channel and lower towards the head. In the main channel the movement of organisms would occur laterally, from one side to another, and vertically between the main channel and the branches. These patterns would produce distinct communities connected by dispersal. The concept of metacommunities couples paradigms that fit the river systems characteristics, where fish fauna in headwater portions are driven by local processes and main channel ones by local and regional processes. This study will be conducted in streams that drain into Pinhal River micro-basin in the upper Paranapanema watershed, south-eastern Brazil. Electrofishing and environment structure data sampling will be conducted in 70-m length stream reaches about 2-km equidistant. Our partial results, conducted in Claro River (Pilar do Sul, SP), pointed distinct communities between upstream and downstream reaches, regarding species composition, richness and diversity (pd0.05). Among the structural variables, the same pattern was found for substrate composition. Increased sample size in the micro-basin is required in order to verify if the same metacommunities pattern is conserved at this scale.